The many existing automation controls are based on using special high-cost-complex machine components. Precision parts are required at each stage, and within each unit, the total-output tolerance is the sum of all the internal errors. Many automation servo units have a complex-signal system to command a movement of a given number of pulses. Each pulse commands an increment-in-motion or change-in-location. These pulses are then converted into a complex-stepper-motor or servo-power-sequence to rotate and cause a linear motion. The pulse-drive requires a precision drive-motor working through a precision gear-box to cause a given twist of a shaft. The shaft has to be mounted in precision bearings, and be made of very precision construction to convert the twist into the required, precise, linear-motion to the travel-ram. Some form of feedback is required in existing automation controls to sense the actual move in relation to the command. All this is hardware is very expensive, and in many systems, special-software is used to avoid major interface problems for electrical commands to provide actual productive work. The whole field of automation and motion control has been changing to encompass special glass-etched scales, rotary and linear encoders, special-stepper and servo-motors as assembled, without any new overall system. A need exists for a redesign, as a means to inject some improved selected complex components into the existing array of numerical control and automation hardware.
Some newer control systems have been developed with laser-beam-transit-time to read “distance” from a given reference point. Special magnetic-encoded scales with complex-markings and other forms of analog-to-digital systems are being used. These more modern controls still only make machines move in accord with input commands. The new sensors have better life and operation in the harsh environment where they are operating. The commands and interface with the physical motion must compare to feedback return signal-readout-information. Computers are needed to handle this type of new extremely complex encryption, and carry that back to the main power control and to a display panel.
High-cost for these systems results from new super-precision-motion-control units. Even a slightly sloppy, gear-tooth-mesh cannot be used in standard CNC systems today. Special zero-back-lash or go-too-far, and-then-back-up special-circuit systems are used, and are required. Many servo-motor packages are very small. This forces the use of long rubbery belts or linkage to extend the motion for a large machine. Most systems decay with age and with wear. Ball screws offer only a tiny, high stress-area-contact to mate the shaft to the nut. Small line pad area is the actual push-surface high-stress interface that is present in all rack and pinion, and all gear-to-gear drive systems. Wear makes for less-accuracy in these prior art system designs using low-contact area interface.
It is therefore an object of the invention to develop apparatus that use simple motion causing drives to power this low-cost exacting and precision-locating and measuring system.
It is another object of the invention to have the apparatus acquire an absolute-location and accurate lock of motion command, to move to “12.3 inches”; or “130.2 MM”; or “12.009 inches”; or “345.01 feet”, as examples.
It is another object of the invention to utilize simple electrical-switching-circuits and low-cost, inexpensive, long-life control modules as means to command and control motion.
It is another object of the invention to develop a practical system to operate at, at least 12 volt direct current signal levels for extreme immunity to electrical noise or electro-magnetic-interference found around work stations.
It is another object of the invention to acquire proper precise digital numeric command location without the need for microprocessors; any complex computers and logic systems; or expensive subassemblies and components.
It is another object of the invention to provide practical-affordable-automation motion and measurement systems for rural America and third-world-countries to automate their process, increase their productivity, with less need for technicians, and high-cost-expensive servicing equipment.
It is another object of the invention to provide a Digit Readout (DRO) with this option as an add-on motion control subsystem; as well as, for use in its own right, as a measurement display for Operator interface.
It is another object of the invention to replace the much-more-complex motion controls using incremental, binary, or Gray codes as encryption and sensing means for rotary and linear systems.
It is another object of the invention to provide the use of the simple straight forward precision rack with selectable lock segments for extreme accurate end of linear or rotary travel.
It is another object of the invention to eliminate, from a selected group of precision pulse-control drive systems components and subsystems now necessarily embedded in current servo drives for Numerical Control (CNC) machines.